The use of an air pump to increase the efficiency of an internal combustion engine is known. These pumps discharge air into the combustion chamber as opposed to the more common technic of allowing the engine or piston dynamics suck air therein. It is also known to drive such an air pump by the crankshaft of the engine through a belt or the like. Many prior air pumps have been located in an engine compartment so as to undesirably increase engine size. Other prior arrangements locate the air pump remotely from the engine induction system which necessitates a bulky and costly air distribution tube or the like.
A typical type of air pump utilizes a compressor wheel with vanes thereon. Air is introduced to the wheel's central portion in the axial direction. Air is directed from the peripheral edge of the wheel in a radial direction. The pump discharge air is typically collected in a scroll shaped housing or the like. This arrangement is bulky at least in the radial direction and generally does not easily fit within the confines of modern engine compartments. Examples of this arrangement are disclosed in U.S. Pat. No. 3,832,089 to Moellmann and U.S. Pat. No. 2,851,024 to Meeder.
Resultantly, desirable characteristics of engine air pumps include compactness and the capability to mount the air pump in a cramped engine compartment. To a limited extent, an air pump like this is disclosed in U.S. Pat. No. 4,693,669 to Rogers. A radial impeller is disclosed therein and air is directed radially outward and then rearwardly into a collector housing. The air flow is subsequently directed through tubing to the engine intake.